The volumes of the sponge cakes prepared by using different baking powder formulas and rates were determined with a reasonable mathematical method constituted by us. The volume index and the total volume index values were calculated according to American Association of Cereal Chemists (AACC) method 10-91 and the methods presented in literature. Then, these values were compared with volume calculated by mathematical method under consideration. In the study, the lower and upper part of the cake were taken as the shape of a cylinder and a sphere, respectively, and then volume of these two parts were calculated separately. A high correlation is observed between the index values presented in literature, and the volume values determined with the mathematical method carried out in this study. Therefore, the mathematical method performed in this study can easily be applied to calculate the volumes of the cakes which are prepared by using baking pans, described in AACC method 10-90 or the pans similar to ones in AACC method 10-90.